Crystallization of amorphous AlDy- and AlDyCo-alloys

Partially or fully amorphous Al89Dy11, Al84Dy11Co5 and Al84Dy6Co10 alloys were prepared by melt spinning. The amorphous to crystalline and subsequent transitions were studied with X-ray diffraction, electrical resistivity, thermal and microhardness measurements. The transformation kinetics were analysed in terms of the classical and the generalized Johnson–Mehl–Avrami–Kolmogorov models for nucleation and growth processes. In amorphous Al89Dy11, crystallization begins with α(fcc Al) formation closely followed by γ(Al3Dy), which transforms to α(Al3Dy). Addition of Co increases the stability of the amorphous states. The first crystallization process in the ternary alloys is eutectic-like; nanocrystals are present in Al84Dy6Co10. Annealing in the region of structural relaxation retards subsequent crystallization.